The University of Chicago submits this proposal in response to RFA-RR-09-008 to construct The University of Chicago Biomedical Cleanroom to support basic research in biomedical science. Many forefront areas of experimental biomedical research rely upon customized, investigator-designed probes and devices that are fabricated in highly-controlled environments that are low in airborne dust, microbes, aerosols, and chemical vapors than can contaminate or damage the devices that are being fabricated. In particular, the deposition and lithography tools that were once the exclusive domain of microelectronics R&D have enabled the development of microelectrode arrays, microfluidic devices, surface-spectroscopic probes, integrated "Labs on Chips", and similar concepts that are indispensible in contexts ranging from fundamental research on biological molecules, systems, and organisms to real-time clinical diagnostics. Cleanrooms that provide the controlled environment necessary to produce these probes, devices, and chips are increasingly common at major research universities. The University of Chicago has identified a user group consisting of at least 21 investigators with NIH-sponsored research programs that span the range from inquiry into fundamental biological questions, to processes associated with specific human diseases. We expect this user group to grow significantly as other NIH-supported investigators become aware of the capabilities the cleanroom provides. The user group includes investigators from departments in the biological and physical science divisions as well as researchers from the University's medical complex.